This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Transgenic mouse models are invaluable tools to not only precisely determine structure and functional relationships for specific gene products but also to provide tractable model systems for inherited human diseases. In particular, they can be used to examine inherited skeletal muscle diseases providing a suitable preparation can be found. Most of the data from mammalian skeletal muscle in the literature is from so called skinned in vitro preparations that have a number of advantages but are not truly in the physiological state. The purpose of this experiment was 1) evaluate the utility of the intact mouse EDL muscle as a preparation for small-angle x-ray fiber diffraction experiments and 2) Map out basic structure function changes as a function of temperature as a way of gaining familiarity with the new preparation.